I said in another threat WAAAY back when, I'm not sure of who'd exactly be Faction 5, but there is a few oppertunities and options sitting around 40k that'd be potential usefulness. If anyone's going in first, I have no doubt Dark Eldar for ease of resources (though will require entirely new Wargear due to less soulstones and more spikeys), Necrons due to popularity (though like most, new modelwork and details will be required, as will balancing Reanimation Protocols and similar tropes of em), Sisters due to very similar weapons options for the other factions (though will force more modelwork, AND both figuring out how allied forces will work and the subject of flamers) Daemons as we'll probably see AI of them sooner rather than later for ka-os marines and then all you'd have to do is add them as a faction (then again, problems with allied forces, AND we have the same reason they don't want player Nids, they may act more unnatural.) and Tau again for popularity (though that would mean a HUGE amount of work for added player models due to all the various powersuits the Tau use). I personally wouldn't really hold my breath too much on Tau to show up immediately though, or for that matter Guard for similar reasons - power level would put them durabilitywise lower than Space Marines and Eldar, and the fact they rely on vehicles to play will lead to painful moments without the massive support abilities.
not sure why tau are winning. to quote the Emperor "they dont even do melee' they are the most dishonourable of races *giggle*
Necrons be more of a PVE race ta me. Tau are too weak fer melee and den ya would have ta add Kroot and Power suits. Imperial Guard should have der own game, no need fer dem ta get en da way of da Spess Marines. Dark Eldar because reasons!
Lets add the Loxatal mentioned in the Gaunt's Ghosts series. They run on walls and have fletchet flak type guns mounted to their torsos. I think they used spears for melee as well.
